Exhibit 99.1

FOR THE EXTRAORDINARY GENERAL MEETING OF SHAREHOLDERS OF COLONNADE ACQUISITION CORP.    THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS    The undersigned hereby appoints Remy W. Trafelet and Joseph S. Sambuco (the “Proxies”), and each of them independently, with full power of substitution, as proxies to vote all of the Ordinary Shares of Colonnade Acquisition Corp. (the “Company”) that the undersigned is entitled to vote (the “Shares”) at the extraordinary general meeting of shareholders of the Company to be held on [ ], 2021 at [ ] a.m., Eastern Time, at the offices of White & Case LLP at 1221 Avenue of the Americas, New York, New York 10022, and virtually at https://www.cstproxy.com/colonnadeacquisition/sm2021 and any adjournment or postponement thereof. The undersigned acknowledges receipt of the enclosed proxy statement and revokes all prior proxies for said meeting. THE SHARES REPRESENTED BY THIS PROXY WHEN PROPERLY EXECUTED WILL BE VOTED IN THE MANNER DIRECTED HEREIN BY THE UNDERSIGNED SHAREHOLDER(S). IF NO SPECIFIC DIRECTION IS GIVEN AS TO THE PROPOSALS ON THE REVERSE SIDE, THIS PROXY WILL BE VOTED “FOR” ALL PROPOSALS. PLEASE MARK, SIGN, DATE AND RETURN THE PROXY CARD PROMPTLY. (Continued and to be marked, dated and signed on reverse side) Important Notice Regarding the Availability of Proxy Materials for the Extraordinary General Meeting of Shareholders to be held on [ ]. This notice of Extraordinary General Meeting of Shareholders and accompanying Proxy Statement are available at: https://www.cstproxy.com/colonnadeacquisition/sm2021

Please mark vote COLONNADE ACQUISITION CORP. — THE BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” ALL PROPOSALS. as indicated in this example X Proposal No. 1 — The BCA Proposal — to consider and vote upon a FOR AGAINST ABSTAIN (D) Advisory Organizational Documents Proposal 4D—to approve FOR AGAINST ABSTAIN proposal to approve by ordinary resolution and adopt the Agreement and Plan provisions providing that the affirmative vote of at least two-thirds of the of Merger, dated as of December 21, 2020 (the “Merger Agreement”), by and voting power of all the then outstanding shares of capital stock entitled among CLA, Merger Sub and Ouster, a copy of which is attached to this proxy to vote generally in the election of directors will be required for statement/prospectus as Annex A. The Merger Agreement provides for, among stockholders to (i) adopt, amend or repeal the Proposed Bylaws and (ii) other things, the merger of Merger Sub with and into Ouster (the “Merger”), amend, alter, repeal or rescind Articles V(B), VII, VIII, IX, X, XI, XII and XIII with Ouster surviving the Merger as a wholly owned subsidiary of Ouster of the Proposed Certificate of Incorporation (“Advisory Organizational PubCo (as defined below), in accordance with the terms and subject to the Documents Proposal 4D”); conditions of the Merger Agreement as more fully described elsewhere in this proxy statement/prospectus (the “BCA Proposal”); (E) Advisory Organizational Documents Proposal 4E—to approve FOR AGAINST ABSTAIN provisions permitting the removal of a director only for cause and only Proposal No. 2 — The Domestication Proposal — to consider and vote FOR AGAINST ABSTAIN by the affirmative vote of the holders of at least a majority of the upon a proposal to approve by special resolution, the change of CLA’s outstanding shares entitled to vote at an election of directors (“Advisory jurisdiction of incorporation by deregistering as an exempted company in the Organizational Documents Proposal 4E”); Cayman Islands and continuing and domesticating as a corporation incorporated under the laws of the State of Delaware (the “Domestication” and, (F) Advisory Organizational Documents Proposal 4F—to approve FOR AGAINST ABSTAIN together with the Merger, the “Business Combination”) (the “Domestication provisions requiring stockholders to take action at an annual or special Proposal”); meeting and prohibit stockholder action by written consent in lieu of a meeting (“Advisory Organizational Documents Proposal 4F”); Proposal No. 3 — Organizational Documents Proposal — to consider and FOR AGAINST ABSTAIN vote upon a proposal to approve by special resolution the proposed new (G) Advisory Organizational Documents Proposal 4G—to provide for FOR AGAINST ABSTAIN certificate of incorporation (“Proposed Certificate of Incorporation”) and the certain additional changes, including, among other things, (i) changing proposed new bylaws (“Proposed Bylaws” and, together with the Proposed the corporate name from “Colonnade Acquisition Corp.” to “Ouster, Inc.”, Certificate of Incorporation, the “Proposed Organizational Documents”) of (ii) making Ouster PubCo’s corporate existence perpetual and (iii) Colonnade Acquisition Corp. (a corporation incorporated in the State of removing certain provisions related to CLA’s status as a blank check Delaware, and the filing with and acceptance by the Secretary of State of company that will no longer be applicable upon consummation of the Delaware of the certificate of domestication in accordance with Section 388 of Business Combination, all of which CLA’s board of directors believes is the Delaware General Corporation Law (the “DGCL”)), which will be renamed necessary to adequately address the needs of Ouster PubCo after the “Ouster, Inc.” in connection with the Business Combination (CLA after the Business Combination (“Advisory Organizational Documents Proposal Domestication, including after such change of name, is referred to herein as 4G”); “Ouster PubCo”) (the “Organizational Documents Proposal”); Proposal No. 5—The Stock Issuance Proposal—to consider and vote upon FOR AGAINST ABSTAIN Proposal No. 4 — Advisory Organizational Documents Proposals—to a proposal to approve by ordinary resolution for purposes of complying with consider and vote upon the following seven separate proposals (collectively, the applicable provisions of NYSE Listing Rule 312.03, the issuance of Ouster the “Advisory Organizational Documents Proposals”) to approve by special PubCo common stock to the PIPE Investors, including the Sponsor Related resolution the following material differences between the Cayman PIPE Investor, pursuant to the PIPE Investment (the “Stock Issuance Constitutional Documents and the Proposed Organizational Documents: Proposal”); (A) Advisory Organizational Documents Proposal 4A—to authorize the Proposal No. 6—The Incentive Award Plan Proposal—to consider and FOR AGAINST ABSTAIN FOR AGAINST ABSTAIN change in the authorized capital stock of CLA from 200,000,000 Class A vote upon a proposal to approve by ordinary resolution the Ouster PubCo 2021 ordinary shares, par value $0.0001 per share (the “Class A ordinary Incentive Award Plan (the “Incentive Award Plan Proposal”); shares”), 20,000,000 Class B ordinary shares, par value $0.0001 per share (the “Class B ordinary shares” and, together with the Class A ordinary shares, the “ordinary shares”), and 1,000,000 preference shares, Proposal No. 7—The Adjournment Proposal—to consider and vote upon a FOR AGAINST ABSTAIN par value $0.0001 per share (the “preference shares”), to 1,000,000,000 proposal to approve by ordinary resolution the adjournment of the shares of common stock, par value $0.0001 per share, of Ouster PubCo extraordinary general meeting to a later date or dates, if necessary, to permit (the “Ouster PubCo common stock”) and 100,000,000 shares of preferred further solicitation and vote of proxies in the event that there are insufficient stock, par value $0.0001 per share, of Ouster PubCo (the “Ouster PubCo votes for the approval of one or more proposals at the extraordinary general preferred stock”) (“Advisory Organizational Documents Proposal 4A”); meeting (the “Adjournment Proposal”).    (B) Advisory Organizational Documents Proposal 4B—to authorize FOR AGAINST ABSTAIN adopting Delaware as the exclusive forum for certain stockholder litigation (“Advisory Organizational Documents Proposal 4B”); (C) Advisory Organizational Documents Proposal 4C—to authorize FOR AGAINST ABSTAIN electing not to be governed by Section 203 of the DGCL relating to takeovers by interested stockholders and, instead, be governed by a provision substantially similar to Section 203 of the DGCL (“Advisory Organizational Documents Proposal 4C”); Dated:                , 2021 Signature    (Signature if held Jointly) When Shares are held by joint tenants, both should sign. When signing as attorney, executor, administrator, trustee or guardian, please give full title as such. If a corporation, please sign in full corporate name by the president or another authorized officer. If a partnership, please sign in partnership name by an authorized person. The Shares represented by the proxy, when properly executed, will be voted in the manner directed herein by the undersigned shareholder(s). If no direction is made, this proxy will be voted FOR all Proposals. If any other matters properly come before the meeting, unless such authority is withheld on this proxy card, the Proxies will vote on such matters in their discretion.